ATMOSPHERIC OPTICS EXHIBITION: The Boyden Gallery of St.Mary's College in Maryland is planning a major exhibition of atmospheric optics photos during the summer of 2010. Got images? The deadline for submissions is Nov. 30, 2009. Atmospheric optics expert Les Cowley has the full story.

This kind of aurora borealis--visible to the camera but not to the eye--is called a "photographic aurora." The phenomenon is more common and widespread than you might think. In July, for instance, amateur astronomer Howard Edin recorded photographic auroras at a star party in Valentine, Nebraska: photo. That's pretty far south for "Northern Lights." The key, says Edin, was exposing the scene for a full 30 seconds--the same exposure time Mortensen used in Norway two nights ago.

Astrophotographers should be alert for geomagnetic activity. The next time the solar wind gusts, a great photo could be just half-a-minute away.

SUNSET FIREBALL: If only photographers had faster reflexes.... On Saturday, Nov. 7th, around 5 p.m. Pacific time, a brilliant fireball raced4 across the sky of California's San Francisco Bay, where tens of thousands of people saw it. So far, however, not a single photo of the fireball has emerged. The meteor disappeared into the sunset before anyone could raise his or her camera. When shutters finally started clicking, all that remained was a trail of debris:

"Pepper Dela Cruz took this picture outside the Miramar Restaurant in Half Moon Bay on the San Francisco Peninsula just as the sun was setting," says Doug Moore, who submitted the photo on Pepper's behalf. "It shows debris from the fireball, which lasted for several minutes before dissipating."

The origin of the fireball is still uncertain. Meteor expert Peter Jenniskens of NASA's Ames Research Center believes it was "a small, random asteroid that crashed into our atmosphere. The remains [of the space rock] probably landed in the Pacific Ocean," he says.

More fireballs are in the offing. Earth is passing through a stream of debris from Comet 2P/Encke, and this is causing the annual Taurid meteor shower, which peaks between now and Nov. 12th. The shower only produces about 5 meteors per hour, but what the display lacks in number, it makes up for in dazzle. Taurids tend to be fireballs, slow and very bright. The best time to look is during the hours around midnight when the constellation Taurus is high overhead: sky map.

Note: Based on the time of day and other factors, Jenniskens says "the Bay Area fireball was probably not a Taurid."

Potentially Hazardous Asteroids (PHAs) are space rocks larger than approximately 100m that can come closer to Earth than 0.05 AU. None of the known PHAs is on a collision course with our planet, although astronomers are finding new ones all the time.